Arab states – and Israel – are watching intently as Iran's political convulsions continue, seeking clues to how the unfolding crisis will affect the strategic picture in the Middle East, especially the key issue of the Islamic republic's nuclear ambitions.

In a region where democratic politics are the exception, there is nervousness about the implications of people power on the streets of Tehran. Mahmoud Ahmadinejad is deeply unpopular – but mass protests worry all autocrats.

Israel

Officially and in public, at least, Israeli officials have spoken of their deep concern about Ahmadinejad's apparent re-election. Israel's rightwing government, under the leadership of prime minister Binyamin Netanyahu, has made a priority of challenging Iran's nuclear ambitions. On Sunday night, Netanyahu said the world's greatest challenge today was "the nexus between radical Islam and nuclear weapons".

In private, Israeli officials appeared to be hoping for an ­Ahmadinejad victory even before the polls opened, despite his vitriolic ­criticism of Israel, his denial of the ­Holocaust and his apparent eagerness for a nuclear weapons programme.

Israeli newspapers quoted several senior officials anonymously saying that a win for Ahmadinejad would help Israel because, as they saw it, none of the candidates differed very much on policy and Ahmadinejad's strong language and blunt actions made him easier to criticise internationally. "Considering the circumstances, he is the best thing that ever happened to us," one foreign ministry official was quoted as saying in the popular Ma'ariv newspaper last Friday.

Ben Caspit, a Ma'ariv columnist, put it even more bluntly that morning: "If you have friends in Iran, try to convince them to vote for Mahmoud Ahmadinejad today … There is no one who will serve Israel's PR interests better than him."

Far fewer were the voices who questioned that line of thinking. Among them was Aluf Benn, a Ha'aretz ­columnist who dismissed the support for Ahmadinejad as a "blatant manifestation of the narrow horizons of Israeli strategic thinking".

Lebanon

Recently emerging from their own political upheavals, savvy Lebanese see much of themselves in the people politics unfolding in Tehran.

"It reminds me of our protests," said Haitham Chamas, an activist who helped organise protests in 2005 that brought a million Lebanese on to the streets calling for democratic reforms and the fall of the government.

Just as in Tehran, that opposition was swiftly answered by a huge rally in ­support of the incumbent regime, organised then by Hezbollah, which is allied with Iran and Syria.

Chamas and friends have spent the last week talking of little else but what the historic events unfolding in Iran could mean for Lebanon, where Iranian financing of Hezbollah has divided opinion like never before. The western-backed government, known as March 14, recently beat Hezbollah and its allies in undisputed elections.

"I think if Mousavi's supporters stay on the streets for a week the regime will fall and that will seriously affect Hezbollah," said Chamas.

Hassan Nasrallah, Hezbollah's leader, was quick to congratulate Mahmoud Ahmadinejad on his disputed ­re-election, saying it represented "great hope to all the oppressed people, who reject the powers of arrogance and occupation."

In the Hezbollah-controlled southern suburbs of Beirut, men and women speak admiringly of Ahmadinejad as a true leader of the Shia cause and brand Mousavi "Iran's March 14 candidate".

But for those who see Iran as meddling in Lebanon's affairs, the turmoil in Tehran brings a certain satisfaction. "Now the Iranians are arranging their own house, so perhaps we can expect a little less interference in ours," said Sawssan Abou Zahr, a journalist with An Nahar newspaper.

Iraq

Iran's near neighbour and former arch-foe has remained largely silent in the wake of the post-election revolt.

The Iraqi street is paying little heed to the contested result and national leaders have passed only cursory congratulations to Mahmoud Ahmadinejad in the tumultuous days since.

Lawmakers from the Shia parties have mostly refused public comment to Iraqi media. Many maintain close links to establishment figures in Tehran, and some owe their careers to the patronage of Shia Islamic clerics and supporters.

However, with elections just over six months away, Iraqi MPs are keen to distance themselves from the perception of foreign sponsorship and to concentrate on shaping a sovereign state from six years of occupation.

On the streets, people were ambivalent. "This is the Middle East," said a woman from Baghdad. "Wars and ­revolutions happen all the time."

Gulf states

In Saudi Arabia, Iran's main Arab adversary and leader of the conservative US-backed camp, the government has made no public comment. But there are signs of concern about the effect of the unrest on the Shia majority in the kingdom's oil-producing eastern provinces.

"The Saudis are watching this upheaval and internal divisions with satisfaction," said political analyst Mai Yamani. "It weakens the aggressive ambitions of Iran as they see it. It also damages the prospects for talks between the Obama administration and Iran, which they feel would be at Saudi expense if they succeeded."

The United Arab Emirates, which has a long-running dispute with Iran over three tiny Gulf islands, congratulated Ahmadinejad on his victory. Dubai, home to a large Iranian expatriate community, banned election-related protests. There have also been demonstrations in Kuwait.